NAME¶

modf, modff, modfl - extract signed integral and fractional values from floating-point number

LIBRARY¶

Math library (libm, -lm)

SYNOPSIS¶

#include <math.h>

double modf(double x, double *iptr);
float modff(float x, float *iptr);
long double modfl(long double x, long double *iptr);

modff(), modfl():

    _ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L


        || /* Since glibc 2.19: */ _DEFAULT_SOURCE


        || /* glibc <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE

DESCRIPTION¶

These functions break the argument x into an integral part and a fractional part, each of which has the same sign as x. The integral part is stored in the location pointed to by iptr.

RETURN VALUE¶

These functions return the fractional part of x.

If x is a NaN, a NaN is returned, and *iptr is set to a NaN.

If x is positive infinity (negative infinity), +0 (-0) is returned, and *iptr is set to positive infinity (negative infinity).

ERRORS¶

No errors occur.

ATTRIBUTES¶

For an explanation of the terms used in this section, see attributes(7).

STANDARDS¶

C11, POSIX.1-2008.

HISTORY¶

C99, POSIX.1-2001.

The variant returning double also conforms to SVr4, 4.3BSD, C89.

SEE ALSO¶

frexp(3), ldexp(3)